Face clutch



P 1945- E. WILDHABER 2,384,582

FACE CLUTCH Filed May 22, 1942 3 Sheets-Sheet 1 Zmventor [Riva-s7- wan/mesa Wittering P 945. E. WILDHABER 2,384,582

mom CLUTCH Filed May 22, 1942 s sheets-sneak 2 S p 945. E. WILDHABER 2,384,582

.FACE CLUTCH Filed May 22, 1942 3 Sheets-Sheet 3 Zinnentor EENES r W/LDHH BER Gttorneg the clutch members.

Patented Sept. 11, 1945 FACE CLUTCH Ernest Wildhaber, Bri

ghton, N. Y., asslgnor to Gleason Works, Rochester, N. Y., a corporation of New York Application May 22, 1942, Serial N 0. 444,031

38 Claims.

The present invention relates to toothed face clutches and to methods of producing the same.

The present application covers specifically the novel clutch of this invention. The new method of producing clutches is covered in a separate divisional application, Serial No. 520,463, filed January 31, 1944.

Toothed face clutch members are ordinarily made with radially disposed teeth. Such clutch members can be cut readily with reciprocating planing tools, but this process does not lend itself to mass-production requirements. To increase the speed of production, it has therefore been proposed to cut such clutch members with face-mill cutting tools and this has become an ever more generally used practice. A face-mill cutter cut continuously except for the periods required for indexing the blank, whereas a reciprocating tool is idle on its return strokes as well as during the indexing periods; it cuts only on its strokes in one direction. The face-mill cutter used is ordinarily provided with inside and outside cutting edges, and oneside of a tooth space is cut with the outside cutting edges of the cutter and the opposite side of the tooth space out with the inside cutting edges of the cutter as the cutter rotates in engagement with the work. Such a cutter produces tooth spaces whose opposite sides are coaxial surfaces, of concave and convex lengthwise curvature, respectively. By properly positioning the cutter, however, tooth surfaces may be out which are of zero spiral angle and the teeth may extend substantially radially of the clutch axis.

Where both members of a clutch have the opposite sides of their tooth spaces formed as ooaxial surfaces in the manner described, however, it is necessary to cut the tooth spaces with taper in depth from'end to end, and the taper in depth of the tooth spaces has to be increased over standard proportions of tapering depth teeth in order to obtain the necessary contact between The tooth spaces have to be cut extra deep at their outer ends. Thus, with this process, the structure of the clutch members has to be adapted to the process of cutting.

When the two members of a clutch are cut in the described manner, moreover, with face-mill cutters having straight side-cutting edges, mating'tooth surfaces contact with a so-called bias bearing, that is, with a bearing which extends diagonally of the teeth from one end to the other. This is of little consequence in the case of fixed clutches, that is, clutches whose members are 'bolted together in use, but it is a detriment in the case of releasable clutches, for the loadcarrying capacity of th clutch varies as the members move into and out of full engagement. Of course, the formation of bias bearing can "be avoided by using face-mill cutters of the spherical type, but they are more dimcult to make than-the simple, straight-sided-blade cutter.

Another difficulty that arises in connection with releasable-type toothed face clutches is the provision of suitable chamfer on the teeth. The teeth have to be chamfered to facilitate engagement while in motion. The chamfered portions of the teeth should be so formed that there will be no concentration of the load at one end of the teeth, even when only the chamfered parts are in engagement.

One object of the invention is to provide a toothed face clutch whose members may be made accurately at low cost and in which two sides of the teeth of a clutch member can be cut or ground simultaneously to mesh without bias bearing.

Still another object of th invention is to provide a toothed face clutch which will be insensitive to slight errors in cutting and to hardening distortions and which will carry properly the transmitted loads, without the loads being unduly concentrated at the ends of the clutch teeth.

A further object of the invention is to provide a toothed face clutch in which the two members may have well rounded tooth bottoms and rounded or chamfered tooth tops so that only a moderate clearance will be required between the bottoms of the tooth spaces and the tops of the teeth of the two members of the clutch and the I maximum effective tooth height may be employed.

Another object of the invention is to provide a toothedface clutch'member of such form that two tooth sides may be cut and the tops and bottoms thereof rounded simultaneously.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the method of the present invention, a complete-departure from previous practice is made, both in the cutting of the sides of the teeth and in the chamfering thereof. A facemill cutter of large diameter is used and the cutter is so positioned that it will cut at two spaced points on its periphery simultaneously. to cut or chamfer simultaneously opposite side surfaces of two spaced teeth of the blank. Heretofore face-mill cutters have been employed, at most, to cut simultaneously opposite sides of a single tooth space of a blank.

In the cutting of the side surfaces of the teeth, by the method of the present invention, the cutter is preferably so positioned that its axis is parallel to the clutch axis, and teeth of uniform depth from end to end may be out. In the chamfering of the teeth, the cutter is positioned with its axis inclined to the clutch axis so as to cut chamfered surfaces which approximate helicoidal surfaces of varying lead. When both members of a face clutch have such chamfered surfaces, the clutch will carry properly the transmitted load, even when only the chamfered portions of the teeth are in engagement.

In the cutting of the side tooth surfaces of the two members of a clutch, the preferable method is to cut one member with a cutter whose finish-cutting edges are all outside cutting edges and the other member with a cutter whose finishcutting edges are all inside cutting edges. With the first cutter, opposite side tooth surfaces will be out simultaneously on spaced teeth of the blank which are longitudinally concave. With the second cutter, opposite side tooth surfaces will be cut simultaneously on spaced teeth of the blank which are longitudinally convex. Thus one clutch member will have teeth whose opposite sides are longitudinally convex, and the other clutch member -will have teeth whose opposite sides are longitudinally concave.

By using a cutter for cutting one clutch member whose outside cutting diameter at mean cutting depth is equal to the inside cutting diameter of the cutter, which is used for cutting the other clutch member, the two clutch members have full length tooth contact when in engagement. Ordinarily, however, it is preferred to have the clutch members engage with less than full length tooth contact. This can be accomplished by making the inside cutting diameter of the cutter, which cuts one of the clutch members, smaller than the outside cutting diameter of the cutter which cuts the teeth of the other clutch member. The mating clutch teeth then will have less than full length contact, and may neously with the cutting of the sides of the teeth, because the teeth of a clutch member produced lby the method of this invention are of constant depth from end to end. The top rounding edges and the bottom rounding edges can therefore follow parallel paths as the blades of the cutter travel from end to end of a tooth space in the cutting of the sides of the tooth space. Y

The teeth of releasable clutches are, however, differently chamfered. In chamfering, a facemill cutter with concave cutting-edges is employed. This afiects the cutter diameter. to be used. The cutter, as already stated, is tilted with reference to the work axis in chamfering so that the tooth surface cut by the chamferin tool will approximate a helicoidal surface of varying lead; and the mean pressure angle of the finish-cutting edges of the chamfering cutter are selected in accordance with the amount of this tilt.

It is to be noted that in its chamfering phase, at least, the invention is not limited to use in the production of clutch members having longitudinally curved side tooth surfaces. .The invention may be employed, also, foiinstance, in the chamfering of clutch members having radially disposed teeth with longitudinally straight tooth sides.

Several different embodiments of the invention are illustrated in the accompanying drawings, in which: I

Fig. 1 is a sectional view showing a pair of toothed face clutch members made according to this invention in engagement, the section being taken in a mean plane, hereinafter referred to as the pitch plane, which is perpendicular to the clutch axis;

Fig. 2 is a fragmentary elevational view of the engaging clutch members;

Fig. 3 is a diagrammatic view, showing one of the clutch members in section in the pitch plane,

and illustrating the method of cutting this clutch have their tooth bearing or contact localized at the longitudinal center of the teeth and disappearing at the tooth ends. Thus the clutch members may be rendered insensitive to slight errors in cutting and to hardening distortions and be able to carry properly the transmitted loads without the loads-being unduly concentrated at the ends of the clutch teeth.

Localization of tooth bearing can be achieved, also, by a modification of the invention in which both members of a clutch are cut with cutters having all inside finish cutting edges. Both members have, then, opposite side tooth surfaces which are longitudinally convex, andthe j mating tooth surfaces of the two members engage, therefore, with less than -full length tooth contact.

In all of the described embodiments of .the invention, the clutch members will have side tooth surfaces which are longitudinally curved. Despite this, however, the cutters used in cutting them may be so positioned that the tooth sides have a radial direction at a mean point in their length, and to all intents and purposes, therefore, the clutch members themselves have substantially radial teeth. v

The teeth of the members of a fixed clutch can be rounded ofi at top and bottom simultamember;

Fig. 4 is a part elevational, part sectional view taken at right angles to that of Fig. 3, further illustrating diagrammatically the method of cutting this clutch member;

Figs. 5 and 6 are views, corresponding to Figs. 3 and 4, respectively, and illustrating diagrammatically one method of cutting a mating clutch member;

Fig. 7 is 'a diagrammatic view, similar to Figs. 4 and 6, illustrating the cutting of a somewhat modified form of clutch according to this invention;

Fig. 8 is a view similar to Fig. 5. but illustrating diagrammatically how one member of the v clutch may have its tooth surfaces cut to have a slightly different radius of lengthwise tooth curvature from the engaging tooth surfaces of the mating clutch member, so that the two clutch members may engage with a localized tooth bearing;

Figs. 12 and 13 are similar views, illustrating how opposite sides of spaced teeth of one member of a clutch may be chamfered according to the present invention;

Figs. 14 and 15 are similar views, illustrating the preferred method of chamfering the teeth of the other member of the clutch;

Fig. 16 is a fragmentary elevational view, illustrating diagrammatically how the tops and bottoms of a tooth of a member of a fixed clutch may be rounded simultaneously with the cutting of the side of the tooth when the clutch member is constructed according to the present invention; and

Fig. 17 is a fragmentary elevational view of a releasable clutch member made according to this invention, and illustrating particularly the character of the chamfered portions of the tooth surfaces of this clutch member.

In Figs. 1 to 6 inclusive, the two members of a fixed face clutch made according to this invention are designated at 20 and 2 I, respectively. The member 20 has teeth 22 whose opposite sides 23 and 2d are longitudinally concave. The member H has teeth 25 whose opposite sides 26 and 27 are longitudinally convex. In one embodiment of the invention, the radius of lengthwise curvature of the concave sides of the teeth of one clutch member 23 is equal to the radius of lengthwise curvature of the mating convex sides of the teeth of other clutch member 2i, and the teeth of the two clutch members, when in engagement, have therefore full length contact. This is the condition illustrated in Fig. l. The common axis of the two clutch members is here denoted at 28.

For cutting the sides of the teeth of the clutch member Zii, a face-mill cutter 30 is employed which has outside finish cutting edges 3!. Instead of tilting the cutter, as would be conventional practice, so as to avoid having it cut at more than one part of the tooth zone of the work, the cutter is deliberately positioned and its outside diameter is made sufiflciently large for it to cut the opposite sides 23 and 24 of two spaced teeth of the clutch member simultaneously. Thus, it is positioned with its axis 32 parallel to the axis 28 of the work and in the embodiment illustrated in Fig. 3, its outside cutting diameter is sufliciently large for the cutter to finish simultaneously one side 23a of a tooth 22a and the opposite side 2411 of a tooth 22b which is spaced a distance of five pitches from the tooth 22a.

Cutting is effected by rotating the cutter in engagement with the work while simultaneously eflecting relative depthwise feed movement between the cutter and work until the tooth surfaces have been cut to full depth. After the cutting of one pair, of tooth' surfaces, the cutter is withdrawn from engagement with the work and the work is indexed through one pitch. Then the cutter is fed back into the work and another pair of tooth surfaces are finish-cut as before. The pressure angle or inclination of the outside cutting edges 3| of the cutter will correspond to the pressure angle or inclination of the sides of the teeth to be cut. a

The mating member 2| of the clutch may have its tooth sides finish-cut with a face-mill cutter 35 which has inside finish-cutting edges 36. This cutter is positioned with its axis 31 parallel to the axis 28 of the clutch member and the diameter of this cutter is again such that it will finish-cut,

simultaneously opposite side surfaces of two spaced teeth of the clutch member. position shown in Fig. 5, the inside cutting edges of the cutter-35 cut simultaneously one side 2111 Thus, in the of a tooth'25a and the opposite side 26b of a tooth b of the clutch member.

In the cutting of the clutch member 2|, the

cutter is rotated on its axis 31 and simultaneously fed relative to the work into depth until two tooth surfaces of the work have been finish cut for their full height. Then the cutter is withdrawn from engagement with the work, and the work is indexed. Then the cutter is fed back into the work and the cycle begins anew. The pressure angle or inclination of the inside finish-cutting edges of the cutter at 35 is equal to the pressure angle or inclination of the sides of the teeth of the clutch member at any point 38 in the common pitch surface 33, that is, the pressure angle or inclination of the inside cutting edges 36 of the cutter 35 is equal to the-pressure angle or inclination of the outside cutting edges 3| of the cutter 33.

It will be noted that the finish cutting edges of the two cutters and are straight and of positive pressure ang1e. Nevertheless, there is no difiiculty with reference to bias bearing because the teeth of the two clutch members are cut to be of constant depth from end to end. Thus relatively simple types of cutters may be employed.

The two clutch members 20 and 2! will engage with full lengthwise tooth contact because the outside cutting edges H of the cutter 3B and the inside cutting edges 36 of the cutter 35 constitute complementary cutting surfaces which match each other and which have the same radii at points 3% and 38, respectively, in the pitch plane 33. Where it is desired that the mating tooth surfaces of the clutch members mesh with 10- calized tooth contact instead of full length contact, one member of the pair may be cut with tooth surfaces having a different radius of lengthwise curvature from the tooth surfaces of the mating member of the pair. Thus the clutch member, which is to mesh with the clutch member 20, may be provided with teeth whose side surfaces have different lengthwise curvature, as has the clutch member 45 shown in Fig. 8.

The clutch member 45 has its tooth surfaces finish-cut by a face-mill cutter 46 whose inside cutting diameter is considerably smaller than the inside cutting diameter of the cutter 35 of Figs. 5 and 6. The cutter 46 cuts Opposite sides 48 and 49 of teeth 50 which are spaced three pitches their full height. Then the cutter is withdrawn from engagement with the blank, and the blank indexed.

Fig. 9 is a view similar to Fig. 1 showing fragmentarily how the teeth 22 of the clutch member 20 engage with the teeth 50 of the clutch member 45 when the two clutch members are in engagement. As will be seen, the opposite sides 23 and 24 of the teeth 22 of the clutch member 20 contact with the mating opposite sides 48 and 49,

respectively, of the teeth 50 of the clutch mem ber 45 with less than full lentgh contact. By suitably positioning the cutter 46, the contact between the mating tooth surfaces of the two clutch members can be concentrated midway the length of their teeth so that the clutch members mayaccommodate themselves to slight errors in cutting and carry properly the transmittedloads without danger of these loads being unduly concentrated at the ends of the teeth.

Localization of tooth bearing can also be ob tained by making the sides of the teeth of both clutch members longitudinally convex. Thus the teeth of two clutch members, like the clutch member 2i of Fig. 5, would engage with one another with a localized tooth contact. This construction may be employed especially where the diameters of the clutches are quite small.

Many advantages result from the cutting of the clutch members with teeth of constant depth from end to end, additional to those already indicated. Thus, as illustrated in Fig. 16, it is possible to cut the sides and round off the tops and bottoms of the teeth of such clutch members simultaneously. To do this, a face-mill cutter may be employed whose blades 55 have finishcutting edges 56 which are rounded at the base of the blades, as indicated at 51, and which are also rounded off, as indicated at 58, where they join the tip cutting edges 59 of the blades. In the instance shown, the finish-cutting edge 56 of the blade is straight and inclined to the axis of-the cutter for the greater part of its height, that is, of positive pressure angle.

When this cutter is rotated in engagement with a clutch blank 64 and simultaneously fed relatively in depth, it will cut tooth surfaces on the blank which are of straight profile and positive pressure angle for the greater portion of their heights, as indicated at 60, and which have wellrounded tooth space bottoms as denoted at 6! and rounds at their tops as indicated at 62.

The method of the present invention is not limited to production of clutch members having side tooth surfaces of positive pressure angle. Thus, as illustrated in Fig. 7, it may be employed also in the production of clutch members whose side tooth surfaces 66 and 61 are parallel to the clutch axis 68. Here a face-mill cutter i is employed that has outside cutting edges H or inside cutting edges 12 that are parallel to the cutter axis 13; the cutter is positioned so that its axis 13 is parallel to the clutch axis 68; and the tooth surfaces of the clutch'members are produced by rotating the cutter on its axis while equally to the chamfering of the teeth of clutch members whose opposite side tooth surfaces are longitudinally convex.

For the chamfering operation, a face-mill cutter 85 may be employed which has outside cutting edges 88 that are of concave profile shape.

This cutter is tilted with reference to the work so that it axis 81 is inclined to the root plane 88 of the work and the cutter is revolved in engagement with the work. shown, the cutter is tilted in a direction lengthwise of the engaged clutch teeth only so that only one side surface of the clutch teeth is chameffecting relative depthwise feed movement between the cutter and work until the tooth surfaces of the work have been cut for their full height. By suitably rounding the blades of the cutter as illustrated in Fig. '7, rounded tooth space bottoms 69 may be formed on the work. The cutting edges of the cutter may also be formed, if desired, in a manner similar to that shown in Fig. 16, to round off the sides of the clutch teeth at their juncture with the tops of the teeth.

Clutch members, such as shown in Figs. 1 to 6 inclusive and 16, are intended primarily for us in fixed clutches where the two clutch-members are rigidly bolted together in use. For releasable clutches, which are intended to be repeatedly engaged and disengaged, the side surfaces of the teeth may be cut in the manner described, but it is desirable to chamfer the teeth insuch way that the teeth will carry the required loads even when the chamfered portions only of the teeth are in engagement and not-have these loads concentrated at one end of the teeth. The desired type of chamfer may be produced by application of the cutting method of this invention to the production of chamfered tooth surfaces which approximate helicoidal surfaces of varying lead. The principles of the chamfering operation are fered at a time. The cutter axis 81 is inclined to a normal 89 at a point 89 in the chambered portion of the clutch member. Due to the inclination of cutter axis and the concave cutting profile 86, a. lengthwise curve of larger radius will be cut on the chamfered portions of the teeth than the radius of the chamfering cutter. It is for this reason that the diameter of the chamfering cutter is made smaller than the diameter of the cutter which cuts the longitudinally concave sides 82 and 83 of the teeth. Due to the tilt of the chamfering cutter, also, the inclination of the chamfered surface will vary along the length of the clutch teeth. Thus a chamfered surface will be produced on each tooth which will approximate, as desired, a helicoidal surface of varying lead, having its pressure angle increasing with increasing distance from the clutch axis.

The principle on which the chamfering operation depends is further illustrated diagrammatically in Fig. 12. Here 90 denotes the teeth of a clutch member 9| whose opposite side tooth surfaces 92 and 93 are of longitudinally concave shape and approximately zero pressure angle. As previously stated, the chamfered surface, which it is desired to produce on each tooth, is a helicoidal surfaceof varying lead. This is a surface such as might be produced by a line, preferably a circular arc, which is moved about the clutch axis 95 and simultaneously fed in the direction of the clutch axis at a varying rate. The intersection of such a helicoidal surface with any plane perpendicular to the clutch axis will be a circular arc. Thus, the intersection of the cham fered surface of a tooth with a plane containing the tops of the clutch teeth and perpendicular to the clutch axis might be a circular arc such as denoted at 96 in Fig..12, while the intersection of the chamfered portion of a tooth with a plane perpendicular to the clutch axis but somewhat lower down on the chamfered surface might be a circular are such as denoted at 81. The two circular arcs 96 and 9'! have the same radii of curvature 98 but their centers of curvature 88 and I00, respectively, are displaced from one another about the axis of the clutch and in the direction of this axis 85.

Such a helicoidal surface of varying lead can be approximated very closely, as already stated, by a surface of revolution of circular arcuate profile shape. .This is the kind of surface produced by a rotating face-mill cutter when the cutter hascutting edges of circular arcuate profile shape and the axis of the cutter is tilted with reference to the clutch member to out further In the instance down onthe tooth profiles at the outer ends of the clutch teeth than at the inner ends thereof.

Figs. 10 and 11 are intendedonly to illustrate the principle underlying the formation of chamfered surfaces by the method of the present invention. In actual practice, the cutter employed for chamfering is so positioned and tilted that it chamfers simultaneously opposite sides of spaced teeth of the work. This is illustrated in Figs. 12 to 15 inclusive for both clutch members having longitudinally concave tooth surfaces and clutch members having longitudinally convex tooth sur faces.

Figs. 12 and 13 show the chamfering of the teeth of a clutch member whose teeth 90 have longitudinally concave tooth sides 92 and 93. Here the chamfer is produced by a face-mill cutter I having outside cutting edges I06 of concave circular arcuate Profile shape. This cutter is so tilted relative to the work that its axis I01 intersects the axis 95 of the clutch member instead of being oil-set therefrom as is the case with the cutter of Figs. -and 11. The outside cutting edges I06 of this cutter will then chamfer opposite side surfaces on spaced teeth of the work which will be surfaces of revolution whose profiles have varying inclination from end to end of the teeth. In Fig. 12 the cutter is shown in the position where it is chamfering the top portions of the sides 92a and 93b, respectively, of the teeth 90a and 90?), respectively, of the clutch. chamfering is effected simply b rotating the cutter in engagement with the work while effecting such relative depthwise feed between cutter and work as is required to chamfer the tooth surfaces to the desired depth; and after one pair of tooth surfaces has been chamfered, the cutter is withdrawn from engagement with the work and the work is indexed.

The convex side surfaces H3 and N4 of the teeth N2 of the clutch member llll, which is to engage with the clutch member 9 i, may be chamfered with the inside cutting edges of a cutter. It is preferred, however, particularly where the diameter of the cutter gets large, to use a cutter having outside cutting edges to chamfer the side surfaces even of teeth whose sides are longitudinally convex. This is illustrated in Figs. 14 and 15. Here the opposite side surfaces H3 and ll l of the teeth H 2 of the clutch member Hll are chamfered by a face-mill cutter H5 having outside cutting edges H6 of circular arcuate profile shape and suitable pressure angle. This cutter is so tilted with reference ,to the work that it will chamfer simultaneously opposite sides of spaced teeth of the work. Its axis H8 is inclined to the axis III of the work but lies in the same plane as the axis of the work and intersects the axis of the work. Thus, as shown in Fig. 14, the cutter may chamfer simultaneously the opposite side 3a and ll4b of the spaced teeth 2a and H 2b, respectively, of the work. The chamfering is effected by rotating the cutter on its axis I I8 in engagement with the work while the work is held stationary on its axis l M. After a pair of tooth surfaces have been chamfered, the cutter is withdrawn from engagement with the work and the work indexed. 120 denotes a normal at point |2l to the chamfered portion |l3a of one side of the tooth I I2a of the work.

While it is preferred to use chamfering cutters whose cutting edges are of circular arcuate profile shape, the invention is not restricted to the use of such cutters. The chamfering edges might [be of any other, suitable shape, as, for instance, involute curvature.

A portion of a clutch member H0 whose teeth .2 have chamfered portions produced according to the method of this invention, is shown on an enlarged scale in Fig. 17. The chamfered portions of the teeth are convex surfaces of revolution. It will be noted that the inclination of the chamfered portion ll! of each tooth surface increases with increasing radial distance from the clutch axis. Thus, the profile curve I l 9 of the chamfered surface at the outer end of a clutch tooth has a greater inclination to the tooth side H4 than the profile curve H9 at the inner end of the chamfered portion of the tooth.

In the embodiment shown in Fig, 17, the sidecutting edges of the chamfering cutter are so constructed that the chamfered portions of the teeth adjoin the side surfaces of the teeth smoothly without break. The juncture may be at an angle, however, but, if so, this is preferably kept as small as possible.

The method of the present invention is not restricted to the chamfering of clutch members having teeth with longitudinally curved sides. It may be used also, as will be obvious, in chamfering clutch members having radially disposed teeth and tooth sides. chamfered surfaces in the form of helicoidal surfaces of varying lead are essential to such clutch members also, if concentration of the loads at one end of the teeth is to be avoided when the clutch members are moving into and out of engagement. Here the cutters employed for chamfering will have outside cutting edges like those illustrated in Figs. 12 to 15 inclusive.

While the invention has been described in connection with the use of face-mill cutters, it is to be understood that oscillatory tools might be employed instead. It is to'loe understood, also, that the term cutter is intended to include grinding wheels also and is so used throughout specification and claims.

It is further to be understood that while the invention has been described in connection with the use of cutters having all outside or all inside blades, this part f the description refers to finish-cutting only, and that for rough-cutting or for finish-cutting directly from the solid blank, a cutter might be employed having both inside and outside cutting edges to take out the stock more readily. In this event the pointwidth of the cutter would be less than the finished width of the tooth spaces so that only the side-cutting edges at one side of the cutter would finish-cutthe desired tooth sides of the work.

While several different embodiments of the invention have been described, it will be understood that the invention is capable of further modification, and this application is intended to cover any adaptations, uses, or modifications of the invention. following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A face clutch member having teeth whose opposite sides are curved longitudinally from end to end, the centers of lengthwise curvature of the opposite sides of each tooth lying, respectively, at opposite sides of the tooth.

2. A face clutch member having generally radial teeth, containing longitudinally curved tooth portionswhich are parts of surfaces of revolution, the axes of said surfaces being disposed in planes containing the axis of the clutch member.

3. A face clutch member having teeth, all of which extend generally radially of the clutch axis, opposite sides of each tooth being longitudinally curved, and opposite sides of spaced teeth lyin in the same surface of revolution.

4. A toothed face clutch member having teeth, all of which extend generally radially of the clutch axis, the side surfaces of each tooth being of straight profile and longitudinally curved, and opposite side surfaces of spaced teeth lying in a common surface of revolution.

5. A face clutch member having teeth which are of uniform height from end to end, opposite sides of the teeth being portions of surfaces of revolution whose axes are parallel to the axis of the clutch member, opposite sides of spaced teeth being parts of a common surface of revolution.

6. A face clutch member having teeth, portions of the opposite side surfaces of each tooth of which are curved about centers which lie, respectively.at opposite sides of the tooth, the said portions of opposite sides of spaced teeth lying in a common surface of revolution whose axis is parallel to the axis of the clutch member.

7. A face clutch member having teeth, portions at opposite sides of each tooth being longitudinally curved and having centers lying, respectively, at opposite sides of the tooth, the said portions at opposite sides of spaced teeth lying in a common surface of revolution whose axis is inclined to and intersects the axis of the clutch member.

8. A face clutch comprising a pair of toothed members, one of which has generally radial teeth whose opposite sides are longitudinally convex, and the other of which has generally radial teeth whose opposite sides are longitudinally concave.

9. A face clutch comprising a pair of toothed members, one of which has generally radial teeth whose oppositesides are longitudinally convex, and the other of which has generally radial teeth whose opposite sides are longitudinally concave, the radii of lengthwise curvature of contactin convex and concave tooth sides being equal.

10. A face clutch comprising a pair of toothed members, one of which has generally radial teeth whose opposite sides are longitudinally convex, and the other of which has generally radial teeth whose opposite sides are longitudinally concave, the radius of lengthwise curvature of the convex sides of the teeth of one member being less than the radius of lengthwise curvature of the mating tooth sides of the other member.

ber increasing with increasing distance from the clutch axis, the chamfered portions of opposite sides of spaced teeth being parts of a common surface of revolution.

14. A toothed face clutch member having teeth which are of constant height from end to end whose sides are chamfered at their tops, opposite sides of spaced teeth being parts of a common surface of revolution, the chamfered portions of opposite sides of spaced teeth being also parts of a common surface of revolution whose axis is inclined to the axis of the first named surface of revolution. g

15. A toothed face clutchmember having teeth which are of constant height from end to end whose sides are chamfered at their tops, opposite sides of spaced teeth being parts of a common surface of revolution whose axis is parallel to the axis of the clutch member, and the chamfered portions of opposite sides of spaced teeth being also parts of a common surface of revolution whose axis is inclined to the axis of the clutch member.

16. A toothed face clutch member whose teeth are chamfered along their top edges, the'cnamfered portions of the teeth being longitudinally curved.- and being parts of surfaces of revolution.

17. A toothed face clutch member whose teeth are chamfered along their top edges, the chamferecl portions of the teeth'being longitudinally curved and being parts of surfaces of revolution whose axes are inclined to the clutch axis.

18. A toothed face clutch member whose teeth are chamfered along their top edges, the chamfered portions of the teeth being portions of convex surfaces of revolution whose axes are inclined to and intersect the clutch axis.

19. A toothed face clutch whose members have their teeth chamfered along their top edges, the chamfered portionsof the teeth of one member being of longitudinally convex lengthwise curvature, and the chamfered portions of the teeth of the other member being. of longitudinally concave I lengthwise curvature,

20. A toothed face clutch whose members have longitudinally curved teeth which are chamfered shape.

21. \A toothed face clutch whose members have their teeth chamfered along their top edges at 11. A toothed face clutch member having teeth opposite sides of the teeth, the chamfered p rtions of the teeth of each member being longitudinally concave surfaces of revolution of convex profile shape.

22. A toothed face clutch WhOSe members have their teeth chamfered along their top edges at opposite sides of the teeth, thechamfered portions of the teeth of each member being longitudinally concave surfaces of revolution of convex profile shape whose profiles have increasing inclination to the clutch axis with increasing d-istance from the clutch axis.

bers being longitudinally concave surfaces of revolution of convex profile shape.

24. A toothed face clutch, one member of I which has longitudinally convex side tooth surfaces, and the other member of which has longitudinally concave side tooth surfaces, both members having their teeth chamfered along their top edges, the chamfered portions of the teeth of both members being longitudinally concave surture, and the chamfered portions of the teeth of the other member being of longitudinally concave lengthwise curvature, the radius of lengthwise curvature of the longitudinally convex surfaces of one member being less than the radius of lengthwise curvature of the longitudinally concave surfaces of the mate member.

26. A toothed face clutch member having 1ongitudinally curved teeth whose sides are parts of surfaces of revolution and which are chamfered along their top edges, the chamfered portions of the teeth being parts of surfaces of revolution whose radii of lengthwise curvature are less than the radii of lengthwise curvature ofoorresponding sides of the teeth.

27. A toothed face clutch member having 1ongitudinally curved teeth whose sides are parts of surfaces of revolution and which are chamfered along their top edges, the chamfered portions of the teeth being parts of surfaces of revolution whose axes are inclined to the clutch axis and whose radii of lengthwise curvature are less than the radii of lengthwise curvature of the corresponding sides of the teeth. 1

28. A toothed face clutch member having longitudinally curved teeth which are chamfered along their top edges, the chamfered portions of the teeth being radial of the clutch axis at mean points in their lengths, and the inclination to the clutch axis of the profiles of the chamfered portions varying along the length of said portions and increasing with increasing distance from the clutch axis.

29. A toothed face clutch member having longitudinally curved teeth which are chamfered along their to! edges, the chamfered portions of the teeth being parts of surfaces of revolution of circular arcuate profile shape whose axes are inclined to the clutchaxis.

30. A toothed face clutch member whose teeth are chamfered along their top edges, opposite sides of the teeth being parts of surfaces of revolution of straight profile shape, and the chamfered portions of the teeth being parts of surfaces of revolution of convex circular arcuate profile shape.

31. A toothed face clutch member whose teeth are chamfered along their top edges, opposite sides of the teeth being parts of surfaces of revolution of straight profile shape whose axesare parallel to the' clutch axis, and the chamfered portions of the teeth being parts of surfaces of revolution of convex circular arcuate profile shape whose axes are. inclined to and intersect the clutch axis.

32. A toothed face clutch member whose teeth have longitudinally curved side surfaces and are chamfered along their top edges, the sides of said teeth at mean points in their length being radial of the clutch axis, and the chamfered portions of said teeth at mean points in their length being radial of the clutch axis.

33. A toothed face clutch member whose teeth have longitudinally curved sidesurlaces and are chamfered along their top edges, opposite sides of spaced teeth being parts of a common surface of revolution, and the chamfered portions at opposite sides of spaced teeth being parts of a common surface of revolution.

34. A toothed face clutch member whose teeth have longitudinally curved side surfaces that are chamfered along their top edges, opposite sides of spaced teeth being parm of a common surface of revolution, the chamfered portions of said tooth sides being also parts of a common surface of revolution whose axis is inclined to the axis of the side tooth surfaces.

35. A toothed face clutch member whose teeth have longitudinally curved side surfaces and are chamfered along their top edges, the sides of the teeth being longitudinally convex, and the chamfered portions being longitudinally concave.

36. A toothed face clutch member whose teeth have longitudinally curved side surfaces and are chamfered along their top edges, the chamfered portions of the teeth being of convex profile shape and extending generally radially of the clutch axis.

37. A toothed face clutch member whose teeth have longitudinally curved side surfacesand are chamfered along their top edges, opposite sides of spaced teeth being parts of a common surface of revolution whichis of straight profile shape, and the chamfered portions at opposite sides of spaced teeth being parts of a common surface of revolution which is of convex profile shape, boththe sides and the chamfered portions of the teeth extendinggenerally radially of the clutch axis.

38. A toothed, face clutch member whose teeth have longitudinally curved side surfaces and longitudinally curved chamfered portions extending along their top edges, each side of a tooth being curved longitudinally about an axis lying at one side of the tooth, and the chamfered portion at that side of the tooth being curved longitudinally about arr axis lying at the opposite side of the tooth. ERNEST W'ILDHABER. 

